1. Field of the Invention
The present invention relates to an image pickup apparatus.
2. Description of the Related Art
Conventionally, if dust, dirt (hereinafter referred to as “dust”) or the like exists in proximity to a focal plane of a shooting lens of a single-lens reflex digital camera, a shadow of the dust may be imaged onto an image captured by a solid image-pickup element and lower image quality. It is considered that such dust is the dust which enters from outside on replacing a lens or fine abrasion powder generated from a member constituting a shutter or a mirror such as a resin or a metal in conjunction with a movement thereof, for instance. If such dust goes into space between a cover glass of the solid image-pickup element and an optical filter placed in front of the cover glass in particular, it is necessary to disassemble the camera in order to remove the dust. For this reason, the camera is provided with a dust-proofing structure to prevent the dust from coming into the space by shutting down the space between the cover glass of the solid image-pickup element and the optical filter from outside.
However, the dust-proofing structure does not prevent the dust from being stuck to an optical incidence plane of the optical filter, and so there are the cases where the dust sticks to the optical incidence plane of the optical filter. Here, in the cases where the optical filter is placed in a position in proximity to the focal plane, the dust stuck to the optical incidence plane is imaged as a shadow onto an image captured by the solid image-pickup element and may cause image quality to degrade.
There is a proposed construction to clean a cover glass surface or an optical filter surface with a wiper (see e.g., Japanese Patent Laid-Open Patent Publication (Kokai) No. 2003-005254). According to this, it is possible to remove the dust stuck to the cover glass surface of the solid image-pickup element or the optical filter surface without taking off the lens and without disassembling the camera.
However, there are the cases where hard dust such as metal powder attaches to the cover glass surface of the solid image-pickup element or the optical filter surface. In such cases, the cover glass surface or the optical filter surface may be scratched by the dust when the wiper slides along the cover glass surface or the optical filter surface.
Thus, to remove the dust stuck to the cover glass surface of the solid image-pickup element or the optical filter surface without scratching the surface, there is a proposed configuration for vibrating the cover glass or the optical filter (see e.g., Japanese Patent Laid-Open Patent Publication (Kokai) No. 2004-032191). To be more specific, according to this configuration, the cover glass or the optical filter is vibrated by a vibrator so as to remove the dust stuck to the cover glass surface or the optical filter surface by vibration thereof.
In the case of the configuration for vibrating the cover glass or the optical filter, however, the configuration needs to prevent the vibration of the cover glass or the optical filter from propagating to any other member. In the case of vibrating the cover glass of the solid image-pickup element, the cover glass and the members fixed on the cover glass may become separate. In the case of vibrating the optical filter, the optical filter and the members fixed on the optical filter may become separate.